1. Field of the Invention
The present invention relates to a system for front connection between a tubular rail for high-pressure fluid, and to a system for reducing the size of the rail. In particular, the invention relates to a system that enables a reduction in the radial stresses to which the ends of the rail are subjected, for example in a system for supplying fuel for an internal-combustion engine.
2. Description of the Related Art
As is known, in internal-combustion engines with fuel injection, referred to as “common-rail engines”, the fuel is brought up to a high pressure, in the region of at least 1600 bar, by means of a high-pressure pump, which sends the fuel to a common rail, having in general a tubular shape, which is in communication with each individual injector. In addition, the rail must be connected to other elements, such as a delivery duct of the high-pressure pump, a pressure sensor, a pressure-limiting valve, etc.
In modern injection engines, the aim is to reduce more and more the size of the rail, whilst for reasons of costs the target is to simplify its fabrication. Tubular fluid rails are known, made from normal-production pipes that enable the rails to be obtained at a lower cost than the ones obtained by forging. Said rails moreover each have at least one terminal portion that must be connected to a coaxial element of the aforesaid type.
Fluid rails of the known art in general present the drawback of requiring brackets that perform the dual function of enabling gripping of the piece being produced and of enabling its fixing to the engine. In the case where the tubular body is made from a normal-production pipe, the brackets must then be welded, or in any case constrained by means of some other type of connection, to the tubular body with an evident increase in costs and complication in the fabrication process. In the case where the tubular body is obtained by forging, the brackets in any case entail an increase in the weight of the entire system.